This is the data coordinating center's grant proposal for the Convergence Insufficiency Treatment Trial (CITT). The data coordinating center will be housed in the Optometry Coordinating Center (OCC) at The Ohio State University. The CITT is a multi-center clinical trial designed to compare the effectiveness of two active treatment approaches for patients with convergence insufficiency (CI). CI is a prevalent and distinct vision disorder. Typical symptoms include double vision, eyestrain, headaches, and blurred vision while reading or doing near work. It affects approximately 5% of children and adults in the United States and may have a serious impact on an individual's performance in school or work, choice of jobs, and quality of life. Clinical signs of CI include exophoria that is greater at near than at far, a receded near point of convergence, and reduced positive fusional vergence at near. There is no consensus regarding the most effective treatment for CI. Two active treatments are Pencil Push-up therapy, which is the standard of care, and vision therapy/orthoptics. Significant differences exist between the two procedures in cost and number of office visits required, with Pencil Push-up therapy the less expensive alternative. There have been no well-designed studies that compare the effectiveness of these two treatments. A prospective, masked, placebo-controlled study is needed to determine the effectiveness of these active treatments for CI. In the proposed clinical trial, 208 patients between the ages of 9 and 18 years will be randomly assigned to: 1) office-based vision therapy/orthoptics, 2) placebo office-based vision therapy/orthoptics, 3) standard home-based Pencil Push-up therapy, and 4) office-based Pencil Push-up therapy. Measurements of the signs and-symptoms of CI will be collected at the eligibility examination and by masked examiners every 4 weeks during the 12 week treatment phase. Patients who are successful after 12 weeks of treatment (as defined by symptom score) will be followed for 12 additional months. The primary outcome measure is the score on the Convergence Insufficiency Symptom Survey. Secondary measures will include the near point of convergence and postive fusional vergence at near. This application provides the rationale for the design of the clinical trial and a description of the goals and responsibilities of the data coordinating center. This proposal also includes some results from pilot studies performed by the core members of the CITT planning committee including the OCC.